Pressure - Viessmann VITODENS 111-W Installation And Service Instructions Manual

Commissioning, inspection, maintenance
Further details regarding the individual steps
B
A
A Test nipple, heating water expan-
sion vessel
B Test nipple, DHW expansion ves-
sel
Checking gas equipment for tightness at operating pressure
Danger
Escaping gas leads to a risk of
explosion.
Check gas equipment for tight-
ness.
!
Please note
The use of leak detection spray
can result in incorrect functions.
Leak detection spray must not
reach electrical contacts or seal
diaphragm openings on the gas
valve.
40
(cont.)
1. Drain the system until the pressure
gauge indicates "0".
2. If the pre-charge pressure of the dia-
phragm expansion vessel is lower
than the static system pressure, top
up with nitrogen until the pre-charge
pressure is raised by 0.1 to 0.2 bar.
3. Top up with water until the charge
pressure of the cooled system is at
least 1.0 bar and 0.1 to 0.2 bar higher
than the pre-charge pressure of the
diaphragm expansion vessel.
Permiss. operating pressure on the
heating water side: 3 bar
The DHW expansion vessel is to be
checked too. Ensure that the pre-charge
pressure is at least 3bar. A depleted
expansion vessel is indicated by a drip-
ping safety valve located in the cold
water supply pipe.